Effects of medicines on human
that the substances have different physical and chemical properties;
what are the properties of selected substances;
about the most important characteristics of substances belonging to groups of inorganic compounds (oxides, acids, hydroxides, salts);
what are the basic properties of selected organic compounds (e.g. alcohols).
the necessity of strictly following the rules of using medicines as prescribed by your doctor;
the consequences of not following the doctor's instructions when taking medicines;
that the use of excessive amounts of various substances harms human health;
to list and discuss factors influencing the healing and toxic properties of chemical substances.
The healing and toxic effects of chemical substances
Almost all chemicals can have a positive or negative (toxic) effect on the human body. The substance's action on the body is connected with its chemical structure and physicochemical properties as well as the amount administered into the body.
Compounds easily soluble in water and easily dissociating are usually more active, because these are more quickly involved in metabolic processes in our body.
The degree of substance fragmentation is also important, and this applies not only to dissolution processes, for example asbestos dust is harmful if its particles have a diameter less than 1 μm (1 µm = 10Indeks górny -6-6 m) – inhaled causes pneumoconiosis, which leads to lung cancer.
An important role is played by the shape of the molecule (mutual arrangement of the atoms that build it), because the course of many processes in organisms requires a very precise spatial matching of the reacting molecules of chemical compounds.
Not only are the properties important, but also the amount and concentration of the substance administered into the body – dosedose and the manner of its percolation into the body. For medicinesmedicines, the therapeutic dose is determined, i.e. the smallest amount of substance that produces the desired therapeutic effect, without causing serious disturbances in the metabolism of the body.
In toxicology, the dose amounts are determined in relation to the harmful effects of the substance (poison) on the body.
Toxic properties of substances (poisons) are determined on the basis of lethal dose LDIndeks dolny 5050 (Latin dosis letalis), i.e. the amount that causes the death of half of test subjects in the group, and the toxic dose TD (Latin dosis toxica), i.e. the amount of substance that causes pronounced toxification of the body .
Chemical substances can get into our body in various ways, for example through the respiratory tract (aerosols), through the digestive system (powders, liquids) and through the skin and mucous membranes (ointments).
Painkillers
Acetylsalicylic acid (ASA) – one of the first painkillers in the world. Since ancient times people made medicines from plants. In antiquity, cold or rheumatism were treated with extracts from willow bark or raspberry juice. Both of these peculiarities contain salicylates – derivatives of salicylic acid.
Currently, acetylsalicylic acid and its compounds hit the market in the pharmacies under the name aspirin. Aspirin is one of the most popular drugs used in the pharmacology of 20th century.
The analgesic effect of aspirin consists in inhibiting the production of prostaglandins in damaged cells that send information to the brain through nerve fibres. In contrast, anticoagulant action is based on the dilution of blood, which is why people who take high doses of aspirin may have, for example, nosebleeds. Although it is a one‑component, simple drug, scientists are still finding new applications.
It is worth remembering that the systematic use of drugs containing acetylsalicylic acid, especially their abuse, may cause side effects, including stomach irritation. Therefore, the drug is not indicated for people suffering from peptic ulcer disease of the stomach or duodenum. These drugs should not be given to children under the age of 12 due to the risk of Reye's syndrome.
It is a reaction typical for a group of compounds containing in their structure a characteristic element - a phenolic group. In the case of poorly stored or expired medicines containing aspirin, this test allows to determine qualitatively the presence of undesired salicylic acid.
Antacids
Gastroenterologists (specialists in stomach and intestinal diseases) claim that about 5–7% of the population suffers from chronic stomach conditions, and at least 30–40% suffer from these symptoms once a month. People suffering from hyperacidity, associated with too aggressive action of hydrochloric acid on the stomach walls, use various types of neutralizing agents.
Neutralizing agents available in pharmacies contain salts or hydroxides of magnesium, calcium and aluminium. The basis of their action is the binding of hydrogen ions and increasing the pH in the stomach. This leads to partial neutralization of the acid gastric contents, as well as a partial reduction of pepsin (digestive enzyme) activity.
Watch the movie explaining the effect of antacids.
![](https://static.zpe.gov.pl/portal/f/res-minimized/R1aKJcZIjYpS2/2/1XT02svz4Zpek6VutWx6N6Q8Jd42BK3h.jpg)
Film dostępny na portalu epodreczniki.pl
Animacja przedstawia neutralizowanie nadmiaru kwasu w żołądku. Głównym zadaniem żołądka jest trawienie. Proces ten odbywa się dzięki obecności w żołądku pepsyny oraz kwasu solnego. Gdy żołądek wydziela zbyt dużo kwasu solnego, to cierpimy na nadkwasotę. Objawom nadkwasoty działamy stosując leki neutralizujące nadmiar kwasu w żołądku. Działanie takich leków polega na zobojętnianiu kwasów zasadowymi składnikami leku.
The process that takes place in the stomach after taking neutralizing agents can be presented as the equation of neutralization reaction of base with an acid:
Gastric juice is secreted by the glands and epithelial cells of the gastric mucosa. During the day, the stomach secretes 2500–3000 cmIndeks górny 33 of gastric juice with a pH of 1.0 to 1.5. Under physiological conditions, hydrochloric acid has a constant concentration, only its volume in the gastric juice changes. The main role of hydrochloric acid is acidification of gastric juice and facilitating the digestion of proteins and the elimination of bacteria that get into the stomach with food. Heartburn arise as a result of throwing acidic stomach contents into the oesophagus.
Another drug commonly used in the case of stomach conditions is active carbon, also known as therapeutic or activated carbon. The healing effect of this substance is related to its sorption properties. After administration, it has a strong anti‑diarrheal effect. It is used in cases of food poisoning and poisoning with certain drugs and chemical compounds. It is characterized by a large absorbing surface and binds substances that cause poisoning, e.g.: paracetamol, ibuprofen, barbiturates, alkaloids, heavy metal salts. After administration, it is not absorbed from the gastrointestinal tract and is excreted.
Antibiotics – fighting the cause, not only the effects of the disease
To inhibit the growth of microorganisms, especially pathogenic bacteria, medicine uses antibiotics. These are organic compounds with a complex chemical structure, produced from metabolites of mould and fungi. In this way, so‑called natural antibiotics are produced. The medical industry is focused on the production of semi‑synthetic antibiotics:
more effective – stronger with wider range of activity,
chemically more durable,
more resistant to bacterial enzymes,
often cheaper to produce than natural medicines.
Biotechnological methods are used in the production of many antibiotics. The first natural antibiotic was penicillin. It was obtained from mould (a kind of fungi – Penicillium, which appears, for example, in rotten bread, fruits.
Currently, the pharmaceutical industry produces hundreds of antibiotics. Some attack many types of bacteria, others act only against one or two types of bacteria (these are selective).
Antibiotics, as all medicines, should always be taken in the right amount and as directed by your doctor. This is especially important because, apart from killing or neutralizing pathogenic bacteria, these also destroy the bacteria of gastrointestinal tract necessary for human. Very often it causes inflammation of the mouth and mycosis and leads to the multiplication of antibiotic‑resistant strains, which can be a serious health risk. Frequent bacterial resistance to the drug is associated with irrational antibiotic therapy.
Before you conduct the experiment „Testing the properties of acetylsalicylic acid”, formulate a research question and a hypothesis. Write down the observations and conclusions.
Study of selected properties of acetylsalicylic acid - the reaction and presence of salicylic acid in its decomposition products.
beaker,
tube,
water bath,
any medicine containing acetylsalicylic acid,
water,
universal indicator paper,
sodium salt solution,
iron(III) chloride solution.
Place a shredded pill in a beaker, add about 50 cmIndeks górny 33 of water. Check the pH of the solution using the indicator paper.
Put a few cmIndeks górny 33 of solution into the test tube, add a few drops of the sodium hydroxide solution. Heat the tube for approx. 8‑10 minutes in a water bath.
Neutralize the resulting mixture with hydrochloric acid, and then add a few drops of iron(III) chloride solution.
Before you conduct the experiment „Testing how antacid works”, formulate a research question and hypothesis.
How antacid works?
Antacid causes neutralization of acidic substances.
reagents: hydrochloric acid at a concentration of 0.1 mol/dmIndeks górny 33, distilled water, universal indicator strips, antacids’ pills;
equipment: pH meter, test tubes, 100 cmIndeks górny 33 beakers, water bath, mortar, glass rod, thermometer.
Testing the solubility of the pill depending on the temperature. Grind the tablet down in a mortar and investigate its solubility in 50 cmIndeks górny 33 of distilled water at room temperature. Repeat for water at 40°C.
pH measurement of solutions. Using the pH meter, measure the pH of the previously obtained solutions (point 1). Measure the pH of a 0.1 mol/dmIndeks górny 33 solution of hydrochloric acid. Add fragmented pill to 50 cmIndeks górny 33 of hydrochloric acid with concentration of 0.1 mol/dmIndeks górny 33 at 40°C, mixing with glass rod. Measure the pH of the solution obtained. To the solution resulting from dissolving 1 pill in hydrochloric acid (obtained in point 2.a), add a second, fragmented pill. Mix thoroughly. Measure the pH of the obtained solution. Add 10 cmIndeks górny 33 of hydrochloric acid to the solution (obtained in point 2.d.) with a concentration of 0.1 mol/dmIndeks górny 33 at 40°C. Mix thoroughly. Measure the pH of the solution.
Write down the results in the table.
Select correct statements.
- The amount of substance that causes clear poisoning of the body is the minimum dose.
- Acetylsalicylic acid is one of the most commonly used analgesics and antipyretics.
- For acid hyperacidity, substances that acidify gastric contents are administered.
- Medicinal carbon has strongly adsorbing properties, due to which it absorbs harmful substances that cause poisoning and stomach discomfort.
Summary
Chemical substances may affect the human body and cause the desired effect as expected (drugs) or act adversely - toxic (poisons).
This is primarily determined by the dose of the substance and the way it penetrates the body (through the skin, respiratory system or digestive system). When using medication, it is very important to follow the doctor's instructions – take the right doses of the medicine and administer it during a sufficiently long period.
Keywords
Dose, medicine
Glossary
dawka – ilość substancji chemicznej pobrana lub wchłonięta do organizmu określoną drogą, warunkująca brak lub wystąpienie określonych efektów biologicznych; zwykle dawka jest wyrażona w jednostkach wagowych na masę albo powierzchnię ciała, niekiedy dodatkowo – na dobę
lek – substancja wprowadzana do organizmu w celu zahamowania przyczyny bądź objawów choroby